Sweden's Karo Bio has reported that Merck & Co has discontinue the development of one of the oestrogen receptor modulators identified in the companies' 1997 collaboration.
Merck took the decision to discontinue the lead compound in the program after uncovering toxicological problems in the final stages of preclinical testing. The alliance rests on the discovery of a second oestrogen receptor - oestrogen receptor beta - and is focused on finding that drugs that selectively target either the alpha or beta receptor and may lead to new treatments in the women's health arena.
For example, studies have suggested that the proposed cardioprotective role of oestrogen may be orchestrated via the beta rather than the alpha receptor. The receptors also differ in their tissue distribution around the body, and it has been suggested that drugs which inhibit the beta receptor may have activity in breast cancer but lack effects on bone and lipid metabolism.
A second compound remains in preclinical development at Merck, and there are a number of earlier-stage compounds under evaluation, according to Karo Bio.